Add boot record abstraction and MBR implementation

This commit is contained in:
Curle 2021-07-15 23:15:25 +01:00
parent 15ea32dbcd
commit 317d90baf8
2 changed files with 66 additions and 1 deletions

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@ -0,0 +1,65 @@
#pragma once
#include <stdint.h>
#include <stddef.h>
/************************
*** Team Kitty, 2021 ***
*** Chroma ***
***********************/
/**
* @brief Abstract class for partition table implementations.
* The partition table implements a way to store and handle the boot record for any system.
* ! Do not instantiate!
*/
class BasePartitionTable {
public:
// Initialize the partition object
virtual void Init() = 0;
// Get the amount of partitions in the table
virtual uint8_t GetPartitions() = 0;
// Get the offset which, when added to the start of the disk, will provide the start of the given partition.
virtual size_t GetPartitionStart(uint8_t PartitionID) = 0;
// Get the length of the given partition on disk.
virtual size_t GetPartitionSize(uint8_t PartitionID) = 0;
private:
static BasePartitionTable* Primary;
};
/**
* @brief A BasePartitionTable implementation for MBR (BIOS) systems.
*/
class MBRPartitionTable : public BasePartitionTable {
public:
// Initialize the partition object
virtual void Init() override;
// Get the amount of partitions in the table
virtual uint8_t GetPartitions() override;
// Get the offset which, when added to the start of the disk, will provide the start of the given partition.
virtual size_t GetPartitionStart(uint8_t PartitionID) override;
// Get the length of the given partition on disk.
virtual size_t GetPartitionSize(uint8_t PartitionID) override;
private:
// An MBR Partition Table Entry
struct MBREntry {
uint8_t Status; // 0x80 for "active", 0x00 for inactive, all other values are invalid.
uint8_t CHS_First[3]; // Cylinder-Head-Sector address of the first sector in this partition.
uint8_t Type; // Partition type. https://en.wikipedia.org/wiki/Partition_type
uint8_t CHS_Last[3]; // Cylinder-Head-Sector address of the last sector in this partition.
uint32_t LBA_First; // LBA of the first sector in this partition
uint32_t SectorCount; // Total count of sectors in this partition
} __attribute__((packed));
MBREntry* Entries;
};

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* ! Do not instantiate! * ! Do not instantiate!
*/ */
class FileSystem { class BaseFileSystem {
public: public:
virtual void Init(size_t Sector, size_t Size) = 0; virtual void Init(size_t Sector, size_t Size) = 0;
virtual const char* GetName() = 0; virtual const char* GetName() = 0;